With the rapid development of wireless communication systems, the antenna, as a critical component of the system, is required to satisfy a dynamic environment and smaller design space. Therefore, a different design is required to improve the informational capacity and environmental durability of the antenna. The programmable antenna is one potential method of the reconfigurable antenna. The first is to design various working modes on an individual antenna as much as possible, and the second is to choose a working mode through one or more switches. The flexibility of switching among a plurality of working modes can be realized through the programming control of the on-off state. Compared with the conventional reconfigurable antenna, the programmable antenna can realize more working modes, and one working mode can be switched to another in a flexible manner.
Programming technology has long been applied in microwave devices, including amplifiers with programmable transmission gain, an oscillating source with programmable frequency, a programmable filter and programmable digital phase shifter, etc. However, programming technology has not been widely used in the field of antennas. The reconfigurable design of the antenna normally adopts two methods: the reconfiguration of the feeding network and the reconfiguration of the antenna structure. By altering the feeding phase in a different port, the antenna can function under different polarization characteristics so that the reconfiguration of the feeding network can be achieved. However, simultaneously reconfiguring the working frequency of the antenna is difficult because the working frequency of the antenna is mainly determined by the resonance length of the structure. Although the structural reconfiguration of the antenna can alter the working frequency and polarization, the consequent damage to the structure can cause deterioration of performance and the interference between different working modes that cannot be avoided, resulting in limited choices of working modes, which can be realized by this method. In the prior art, the conventional programmable antenna adopts either the array antenna to control an individual unit or the reflective array antenna to control the phase of the reflector programmatically. Nevertheless, both of the two methods have disadvantages of having a big size, complicated feeding way, and use of a large amount of switches. Thus, the present invention aims to provide a reconfigurable patch antenna, having the advantages of a simple structure, various working modes and easy control.